The name is absent

46

(MP-RAGE) sequence optimized for gray-white matter contrast with 1 mm thick sagittal
slices and an in-plane resolution of 0.938×0.938 mm. Functional images were collected
using a gradient-recalled-echo echo-planar-imaging sequence sensitive to the BOLD
signal. Thirty-three axial slices were collected with an echo time (TE) of 30 ms and a flip
angle of 90 degrees. Slice thickness was 3 mm and in-plane resolution was 2.75
mm×2.75.                                                                       ⁱ"

Experimentl

Experimentalparadigm

As shown in Fig. 1, a three by two design was employed, with three categories of
sensory stimulation (tactile-only, auditory-only, simultaneous tactile-auditory) and two
intensities Ofstimulation (strong and weak). The trial duration was 2.75 S, corresponding
to an MRI repetition time (TR) of 2.75 s. Within each TR, acquisition was clustered so
that imaging (with its accompanying sound and vibration) was completed in the first 2 s
of the TR, followed by 0.75 s of silence. During the middle 5∞ ms of this silent interval,
the stimulus was presented, A rapid event-related design was used. Each 5-minute scan
series contained IlO triaIs (corresponding to 110 TRs) with 15 trials of each type and 20
trials of fixation baseline with no auditory or tactile stimulation.

Vibrotactile somatosensory stimuli were delivered using a piezoelectric bending
element (Piezo Systems, lnc., Cambridge, MA) attached to the left hand using non-slip
silicon elastic bandages. The qualitative percept of stimulation was akin to holding a
ringing cell phone set to "vibrate" mode, without any accompanying auditory percept

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